I have reported this one for the first time over a week ago but it didn't get a very big response, much less an official response, yet it continues to make the game practically unplayable for me to this day (unless I play on another map but dustbowl :).

On most maps, after a while (or instantly on join), TF2 suddenly drops framerate from a smooth 150 - 200 to unplayable 15 - 30. I say most maps because it virtually never happens on cp_dustbowl (only once in 2 weeks) yet almost immediately or within an hour on any other map I tried. The only fix that works for me is to completely exit out of the program and restart it.

Since my first report, there were some updates to Steam itself and I believe also one to TF2, but the problem remains.

Except for Steam, nothing changed on my end, but I'll repost my sysinfo for the sake of completeness:

To be clear - I'm trying to figure out whether low memory condition are causing this issue or not. So knowing the results of the pmap command when there isn't a problem, and then when there is would be great...

Here is output from command, when TF2 was OK: http://pastebin.com/PmZ1Xzd8I can't reproduce this bug today, because instead of FPS drop I getting crash every time if game is not running as should.Very interesting is, I can play all maps offline with bots without any issues.When I first play offline game, then later, game is running well online as well with all maps. When I play online on official servers first, mostly game crash.It crashing in this way: I see menu for team select, I can see FPS around 50 (but it is around 0.1FPS in reality), then sounds and video lags for second, then there is some refresh in video and sound and then game is down.I'll try to post log with slow FPS if I can enter into LOW FPS state again.

I think it could be low memory related issue, since game is loading so long in online. Still game is crashing in team selection with lagged screen at 55FPS + some sound loops and then TF2 go down. In wine, all is running OK and loading times are much faster.

Alright I got a pmap after the lag occured: 2927540K, which is on par with all the other samples so it does not appear to be an out of memory thing. I also grabbed a cpu usage sample.

Steam itself used 100% CPU while playing TF2 (already reported bug) and TF2 itself used another 120%. Maybe something is up with that.

Something I noticed, I could play for days on any map without the bug occuring, but after I changed my graphics settings (enable Motion Blur & Anti Aliasing) it happened basically instantly. Might be connected or not.

Update: I was able to fix it by (I assume) forcing a graphics reinitialization. The bug kicked in earlier and I just tried setting AA and Filtering to the absolute maximum. The game hangs for a short time while it applies the settings and the bug was gone, once I set the values back to their old value it was playable again.

Well, Steam is always using 100% while playing TF2, so much is true, but most of the time I still get a playable framerate until it decides to go haywire. But maybe the one will fix the other, I'll just wait and see. Thank you for your efforts!